Hydrophilic contact lenses, i. e. soft contact lenses, have been commercially available for some time. Proper care of these lenses requires that they be disinfected, preferably daily, and that a rinse solution be applied to the lenses prior to insertion in the eye. It is important that the rinse solution, which is also used during the disinfection operation, be sterile so as to prevent ocular infection.
Non-preserved saline solutions were originally used and were made up daily from salt tablets and distilled water. Distilled water was necessary as the lenses are water absorbent and could pick up minerals or other contaminants in the water. Distilled water is not, however, sterile and the risk of ocular infection existed. Attempts to use preserved saline solutions suffered from the disadvantages that a number of patients were sensitive to the preservatives used and the cost of the preserved saline solutions was markedly higher than the patient prepared non-preserved saline solutions. Attempts to use unit dose containers of non-preserved saline solution were not effective as they were prohibitively expensive.
Prior art heat kits, of which Hoogesteger et al, U.S. Pat. No. 3,983,362, is a good example, provided a heat kit for sterilizing the contact lenses while held in a lens case. The lens case included two receptacles into which the lenses were placed along with a pre-measured amount of saline solution. The heat kit would then be operated to heat the contact lenses contained in the lens case to a pre-determined temperature for a pre-determined length of time, that is, until the lenses were sterilized. Hoogesteger did not, however, provide a means for sterilizing the rinse solution which is usually contained in a separate rinse solution bottle. Consequently, patients frequently applied non-sterile rinse solution to the lenses prior to insertion in the eye with the result of a greatly increased risk of ocular infection.
Wagner et al, U.S. Pat. No. 3,801,278, discloses a sterilizing apparatus for hydrophilic contact lenses having dual sterilizing compartments. Each of the compartments has its own heating element and a thermostat control but with a single timer controlling operation of both compartments. One of the compartments is used to disinfect a number of contact lenses, each pair of lenses being held in a separate lens container case, and the other compartment is used to sterilize a large quantity of saline solution contained in a bottle. The apparatus of Wagner is not, however, designed for use by the ordinary wearer of contact lenses but is, instead, designed for use by an optometrist or other eye care practitioner. Additionally, the duration of the sterilization process in Wagner is independent of the actual process needs of both the rinse bottle and the lens cases. Consequently, use of the Wagner device by a patient could result in under-sterilization of one of the containers with the risk therefore of ocular infection.
In view of the above noted disadvantages of prior art heat kits, a new and unique means for insuring the fail safe sterilization of a contact lens case containing a pair of contact lenses as well as a bottle of rinse solution is necessary. The present invention discloses and claims a novel apparatus for insuring patient compliance by requiring that both the contact lens case as well as the rinse solution bottle be positioned in their separate independently controlled heating compartments prior to initiating operation of the heat kit. Should one of the compartments not be filled, then the apparatus will not operate.